Specific External Drive + Specific USB Port = Not Working

[karvala]

Hi guys,

Got a slightly strange problem that I'm hoping someone can shed some light on. Have a Samsung S2 external hard drive, which until recently worked fine with my desktop machine using any of the USB ports, including the two that I have on the top of case. Now, if I plug the drive into either of those ports, I just get a flashing light indicating drive activity that continues indefinitely, but no recognition that anything has been plugged in from Windows (not even showing up in Device Manager).

Here the additional facts which makes it strange:-

(1) If I plug the S2 hard drive into the back USB ports on the desktop, it shows up fine. In addition, if I plug it into any USB port on my laptop, it shows up fine. I can access files on it etc. in these cases without any problem, so the drive itself does not appear to be faulty.

(2) If I plug anything else into the top two USB ports on the case, including other external drives, mouse, flash drives etc.., these all work fine, so there doesn't seem to be anything wrong with these particular USB ports either.

(3) The S2 used to work fine with these two ports as well.

So, the drive is fine, and the ports are fine, but the combination of the two, which used to be fine, no longer is. That's completely mystifying to me. Does anyone have any possible explanation/remedy for this?

Cheers.

 

[fzabkar]

Could it be a power issue?

Port powered 2.5" USB drives usually exceed the port's 500mA current limit during spin-up. Some ports are OK with is, but many are not. In the latter case you could use a Y-cable to pick up power from two USB ports.

Alternatively, you could use Microsoft's UVCView utility to examine your USB devices and controllers:
http://www.users.on.net/~fzabkar/USB_IDs/UVCView.x86.exe

 

[karvala]

Thanks for the reply. I've been thinking along the lines of a power issue myself. Listening to the drive it's clear that it's spinning up, but then stopping, then trying again, then stopping etc., and it's entirely possible that this is due to the inability to draw enough power to complete the spin-up. The theoretical ability of those two ports is the same as the others, but of course they may be slightly underpowered in practice.

That just about works okay to explain why it now likes some ports but not others, but it doesn't explain why until a couple of days ago the drive was quite happy to be connected with those ports. Nothing has changed since in terms of power output from the ports, or any other part of the system, or the power demands of the drive. Unless the drive spin power requirements are somehow linked to the amount of data on it, that is, which I guess might just about be possible, although seems rather unlikely.

Still, I'll definitely try a Y-cable when I have time to pick one up, as that would certainly confirm whether or not it's a power issue; that's a good idea.

 

[dr fulton]

i started a thread on same problem